1. Field of the Invention
The invention relates to a remote control device for controlling apparatuses carried on the body, in particular hearing aids comprising a device responding to a magnetic field, for example, of a magnet separated from the device to be controlled. The responsive device controls a device assuming various defined switching conditions.
2. The Prior Art
A remote control device was proposed, for example, by AT 379 929. In this known solution a single-channel acoustic remote control is provided with an activatable transmitter which transmits signals modulated on a carrier frequency which lie within the response range of a microphone of an allocated hearing aid. A frequency-selective circuit is disposed behind the microphone for separating the control signals from the voice signals. A control circuit is disposed in the signal path for processing the voice signals. A decoder acting on said control signal is disposed in the signal path for processing the control signals.
This remote control device overcomes the difficulties in the operation of the apparatuses, in particular hearing aids, caused by their miniaturization. Thus, particularly persons of advanced age, who usually have a reduced fine motor skills, have difficulties in manually setting the very small adjustment members of hearing aids, for example the volume control. In the known solution, however, a separate power supply is required. Furthermore, the remote control has to be arranged relatively large so as to enable the simple operation by the user.
Furthermore, from the DE-OS 31 09 049 a remote control device of the type mentioned above is known. In this known solution a device responsive to a magnetic field simultaneously forms a device having various, defined switching conditions. This is the case in a reed switch in which the movable contact can be magnetized and thus not only forms the switching device, but also simultaneously a device responsive to a magnetic field. But also magnetic field semiconductor switches were proposed which also form devices responsive to the magnetic field and, at the same time, elements representing the switching device.
Both cases, however, lead to the fact that the switching condition of the switching device only depends on the existence or non-existence of a sufficiently strong magnetic field and that the switching condition of the respectively selected element only remains in the working position as long as a magnet is in the vicinity of the device responsive to the magnetic field. If said magnet is removed, the switching device returns to its rest position.
This, however, is disadvantageous for many applications, because in order to maintain a certain switching condition it is necessary to maintain a respectively strong magnetic field.